Nonuniversal transmission phase lapses through a quantum dot: An exact-diagonalization of the many-body transport problem

TL;DR

This paper uses exact diagonalization to analyze electron transmission phases in quantum dots, revealing nonuniversal behaviors influenced by shape anisotropy, electron-electron interactions, and spin configurations, aligning with experimental observations.

Contribution

It provides an exact many-body calculation approach to explain nonuniversal phase lapses in quantum dots, emphasizing shape and interaction effects.

Findings

No phase lapse for N=1 to N=2 transition.

Pi phase lapse for N=2 to N=3 transition.

Dependence on dot shape and electron interactions.

Abstract

Systematic trends of nonuniversal behavior of electron transmission phases through a quantum dot, with no phase lapse for the transition N=1 -> N=2 and a lapse of pi for the N=2 -> N=3 transition, are predicted, in agreement with experiments, from many-body transport calculations involving exact diagonalization of the dot Hamiltonian. The results favor shape anisotropy of the dot and strong e-e repulsion with consequent electron localization, showing dependence on spin configurations and the participation of excited doorway transmission channels.